Automatic turret-lathe



J. C. POTTER. AUTOMATIC TURRET LATHE. APPLICATION FILED MAR. II, 1919. 1,363,752. Patented Dec. 28, 1920.

UNITED STATES PATENT OFFICE.

JAMES C. POTTER, OF PAWTUCKET, RHODE ISLAND.

AUTOMATIC TURRET-LATHE.

Application filed March 11, 1919. Serial No. 281,977.

T 0 (177 20710222 2'2 may concern:

Be it known that- I, JAMES C. POTTER, of Pawtucket, Rhode Island. have invented certain new and useful Improvements in Automatic Turret-Lathes, and do hereby declare that the following is a full, clear,

and exact description thereof.

In automaticturret lathes, of the class to which my inven ion relates, the automatic changes -of spindle speed and turret slide teed are accomplished by means of a slow moving rotating wheel. called a dog wheel, which carries pins or dogs on its periphery that act to throw the clutches employed to change the gear connection and such 'dog wheel must be geared to run in time with the turret slide-reciprocating means which usually a cam drum. In all machines of this class known to me, in a practical experience of many years, an undue amount of travel of the turret slide has been unavoidable in the accomplishment of the clutch-shifting action by the dog wheel. because of the time required for that action, and such undue movement means diminished output of the machine because of the time consumed in the performance of its speed and feed changing operations. Greater peripheral speed of the dog with consequent faster action of the dogs, could be secured by increasing its diameter, but the unavoidable limitations which the size of the machine imposes. renders such a remedy impracticable. The object of my invention is to reduce to a minimum, the time required for the clutch-shifting action of automatic turret lathes. and to that end my invention consists in the means employed substantially as hereinafter specified and claimed.

In the annexed drawings- Figure 1 is a side elevation of one construction of automatic turret lathe in which. my invention is embodied;

Fig. 2 is a detail side view, with parts in section of the fluid-operated devices for transmitting the action of the dog wheel to the clutches;

Fig. 2 is a top view of part thereof;

Fig. 3 is a detail view in section on line 33 of Fig. 1.

The automatic turret lathe shown in the drawings to illustrate one embodiment of my invention, is one of the well-known Potter & Johnston =automat1cs, shown for example, in my United States Patent No. 1,225,487, issued May 8, 1917.

Briefly described it comprises a head stock 10, supporting a work spindle with its chuck 11, a turret slide 12, a turret slide actuating drum 13, a feed shaft 11 to which the drum is geared, a dog wheel 15 having adjustable dogs 150 on its periphery, and geared to the feedshaft, and three clutches 16, 17 and 18. respectively, which are under the control of the dog wheel to efiect automatically the changes of spindle speed and tool feed at the proper times. The clutches 16 and 1? determine the spindle speed and the clutch 18 the tool feed speed and each is acted on by its own lever 19, as usual, keyed to one of three rock shafts 20 which run from frontto back of the machine.

Thus far described the construction is as usual.

For operating the rock shafts 20, to throw the clutches, I use fluid under pressure, preferably compressed air, which is under the control of valve mechanism actuated by the dog wheel dogs. But little movement of the dog wheel is necessary to actuate the valve and the result is that the clutch-shipping operation is practically instantaneous. To

cite a particular case, with no. greater turret slide travel than three-eighths of an inch, 1 am able to ship the clutch, whereas with a similar machine, and a wholly mechanical mechanism for transmitting the movement of the dog wheel, the time required involved a four inch travel of the turret slide. In some cases as much as one half the time can be saved. In carrying my invention into practice in the machine shown, I provide for each clutch a piston 21 in a cylinder 22, and connect the piston by a rod 23 with oneend of a crank arm 21 on the end of the rock shaft 25 at the front side of the machine. At each end of the cylinder is an air inlet port 26,.to which a pipe 27 runs from a valve chest 28 to which air is supplied under pressure from a suitable source, as by means of a pipe 29 from an air compressor. In the valve chest is a spring-seated valve 30 having a stem 31 which protrudes beyond the chestinto the path of a dog 150 on the dog wheel, so that as the latter revolves, the valve will be pushed off its seat, and thus open communication between the air compressor and the cylinder, and cause the travel of the piston in one direction or the other according as air is delivered to one inlet port 26 or the other. Air is exhausted from the cy1- inder to the valve chest which latter has an exhaust port 32 under the control of the valve stem 31 which uncovers such port when the supply valve is in its seat and moves over the exhaust port to cover the same before the supply valve is unseated. It will be understood that the cylinder and valve mechanisms are alike for each clutchoperating rock shaft, and as shown they may be cast en bloc.

In the case of one of the clutches, besides the movement of the piston to each end of the cylinder, it is desirable to place it in a mid position because thereby an automatic clutch used in the machine is rendered clutch operative, and to accomplish that, I provide a similar cylinder and piston, and dog-controlled valve mechanism. In such case, the piston 33, has on the end of its rod outside the cylinder 34, a block or head 35 with a V-shaped or cam face 36 adapted when the piston is moved outward to engage the adj acent end of the crank arm 24 of the clutch in question and move the same to mid position.

What I claim is 1. An automatic turret lathe having a member that has movements of various speeds, and in the-same direction for performing work, a dog wheel, and speedcontrolling mechanism in combination with dog wheel controlled fluid pressure means for actuating said speed-controlling mechanism.

2. An automatic turret lathe comprising a rotating work holder, means, including a clutch device, to vary the speed thereof when rotating in the same direction, a turret slide, a slide reciprocating drum, a dog wheel, a shaft from which both drum and dog wheel derive their motion, and dog wheel controlled fluid pressure means for actuating said clutch device.

3. An automatic turret lathe having a reciprocating turret slide, a drum to reciprocate said slide, means, including a clutch device, to vary the speed of the drum when rotating in the same direction, a dog wheel having a timed motion relative to the drum, and dog wheel controlled fluid pressure means for actuating said clutch device.

4. An automatic turret lathe comprising a work rotating work holder, means, including a clutch device, to vary the speed thereof, a turret slide, a slide reciprocating drum, a dog wheel, a shaft from which both drum anddog wheel derive their motion, a clutch device to vary the speed of said shaft when rotated in the same direction, and dog wheel controlled fluid pressure means for actuating said clutch device.

5. An automatic turret lathe having a variable speed moving member, its movements at different speeds being in the same direction, means for varying its speed comprising a shiftable element, a dog wheel, and dog-wheel controlled, fluid pressure means for actuating said element.

In testimony that I claim the foregoing I have hereunto set my hand.

JAMES C. POTTER. 

